Unmanned aerial vehicles (UAVs) vary in degrees of sophistication. For example, a class of UAVs used by hobbyists often rely completely on receipt of control signals from a user-operated remote control device. This class of UAVs relies on user input to provide most or all navigational instructions. A more advanced class of UAVs may exchange control signals and/or other data via established signal sources such as mobile telephone towers. This class of UAVs may receive high level instructions such as waypoints, a destination, and/or other parameters, and may implement logic to navigate through airspace based on the high level instructions and other information accessed by sensors on the UAVs and/or information obtained from the established signal sources. A command station may exchange data with a UAV using a mobile telephone network or other established signal source to exchange information, log events, and for other reasons.
Despite existing systems used to provide location information to vehicles, such as global positioning systems (GPS), these systems are not always accessible to provide input to vehicles. For example, a vehicle may be out of range of some systems, weather may interfere with dissemination of information (e.g., heavy rain, fog, etc.), systems may malfunction, and/or systems may be spoofed. Redundant location systems provide value to compensate when existing systems are not available or to provide corrections to location information from existing systems.